The ability to conduct high-speed data communications between remotely separated data processing systems and associated subsystems has become a requirement of a variety of industries and applications, such as business, educational, medical, financial and personal computer uses. Moreover, it can be expected that current and future applications of such communications will continue to engender more such systems and services. One technology that has attracted particular interest in the telecommunication community is digital subscriber line (DSL) service. DSL technology enables a public service telephone network (PSTN) to use existing telephone copper wiring infrastructure to deliver a relatively high data bandwidth digital communication service, that is selected in accordance with expected data transmission rate, the type and length of data transport medium, and schemes for encoding and decoding data.
FIG. 1 is a reduced complexity diagram of the general architecture of a DSL system, having a pair of mutually compatible digital communication transceivers 1 and 3 installed at remotely separated ‘west’ and ‘east’ sites 2 and 4, respectively, and coupled to a communication link 10, such as a twisted pair of an existing copper plant. One of these transceivers, for example, the west site transceiver 1, may be installed in a digital subscriber line access multiplexer (DSLAM) 6 of a network controller site (such as a telephone company central office (CO)). The DSLAM is coupled with an associated network backbone 5 that provides access to information sources 7 and Internet-sourced data 8. As such, the west site transceiver 1 is used for the transport of digital communication signals, such as asynchronous transfer mode (ATM)-based serialized data, from the west central office site 2 over the communication link 10 to the DSL transceiver 3 at the east end of the link. The DSL transceiver 3 may be coupled with a computer 9 at a customer premises, such as a home or office.
In order to delineate respective cells of a received asynchronous transfer mode (ATM)-based serial data stream, transceivers of digital communication networks, such as the transceivers 1 and 2 in the system of FIG. 1, are often equipped with a mechanism that relies upon a priori knowledge of the boundaries (e.g., beginning) of respective bytes of an incoming serial (ATM) data stream. Unfortunately, some wide area network interface devices provide no information concerning the start of payload or start of respective octets, making it impossible for the transceiver equipment to successfully receive and parse ATM traffic.